Its pretty easy Gator. When your logged into your account you should notice a "user cp" tab at the top of your screen. Its in the same row as gallery, hunting tips, recipes, etc. Click on it. That takes you to your user control panel. To update your details just click on one of the links thats in the row that goes down the left of your screen. I believe its the one at the top of that column titled "edit user profile" or something similar to that. Click on save after you have made and or added your changes.
There are also quite a few other things you can do from the user cp page. Like add pics in an album, make friends, add a avatar, etc.
Hope this helps.